Signaling system



I. P. RODMAN.

SIGNALING SYSTEM.

APPLICATION FILED JUNE 23, 1920.

1,405,005, Patented Jan. 31,1922.

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)77772'655653 yma WW Maw oaifiv' wll UNITED ISAAC r. RODMAN, OF WEST ORANGE, NEW JERSEY, ASSIGNOB 'ro NE JERSEY PATENT COMPANY, OF WEST ORANGE, NEW JERSEY, A CORPORATION or NEW JERSEY.

SIGNALING SYSTEM.

Application filed June 23,

T 0 all '10 ham it may concern:

Be it known that I, ISAAC P. RODMAN, a citizen of the United States, and a resident of \Vest Orange, in the county of Essex and State of New Jersey, have made certain new and useful Improvements in Signaling Systems, of which the following is a description.

M 'invention relates to signaling systems and more particularly to automatic railway block signaling systems wherein track circuits containing relays or the like are employed to control the signals or signal control circuits. A,

In practically all signaling systems of this character now in use, the track circuits are supplied either with direct current from primary or storage batteries, or with alternating current of a given frequency fed thereto from a high voltage transmission line by transformers. WVhere direct current track circuits are used, there is more or less danger of failure of operation of the signal for a given block or track section by reason of the entrance of stray currents into the correponding track circuit from outside sources such, for example, as an adjacent track circuit. Where alternating current track circuits are employed the same are, of course, immune to stray direct currents but .are apt to be seriously affected by stray alternating currents. The great majority of alternating current circuits now used are supplied with commercial alternating currents at certain frequencies, and as alternating currents of the same frequencies are often used in alternating current signaling systems, there is considerable danger of the track circuits being affected by stray alternating currents coming from sources wholly outside the signaling system.

One of the objects of my invention is to provide an improved simple, and eflicient system of this character whereby the danger of stray currents either direct or alternating, affecting any of the track circuits is elimi nated.

Another and one of the principal objects of my invention is to provide a railway signaling system which has all the advantages of present-day alternating current railway signaling systems as regards interference by stray or foreign currents, but wherein it is unnecessary to use polarized circuits, or line control circuits, or a transmission line for Specification of Letters Patent. Patented Jan; 31, 1922.

1920. Serial No. 391,102.

supplying the current to the different track circuits, and which preferably embodies-as one of the features thereof the utilization of sources of direct current, such as primary or storage batteries, for the purpose of pro:

ducing in the track circuits current variations or fluctuations, such as alternating'currents, for controlling the relays which are employed to control the signals orci'rcuitcontrol circuits.

More specifically described, my invention consists in producing in each track circuit of a railway signaling system, preferably by the use of sources ofdirecticurrent, such as primar or storage batteries, current variations or fluctuations of a given frequency or frequencies and different from the frequency or frequencies of the current variations produced in any adjacent track circuit,

7 and associating with each track circuit a'relay or relays, or the equivalent, for controlling the corresponding signal or signal control circuits, said relay or relays being tuned to the frequency or frequencies ofthe current variations produced in such track circuit. Preferably the track circuits are'supplied with alternating currents from suitable generators receiving energy from sources of direct current such as primary or storage batteries, and the arrangement is such; that the frequency of the alternating current thu'ssupplied to each track circuit is different from that supplied to any adj acenttrack circuit and also different from the frequencies of any stray currents such as the commercial alternating currents usually employed for the propulsion oftrains or engines on railroads and other purposes. vVher'e more than onerelay is associated with the track circuit of each section,such relays are'tuned to different frequencies which frequencies are different from those to which any of the relays associated with any adjacent track circuit are tuned, and means are provided for producing in each 'track' circuit current variations or altenating currents of different frequencies, which frequencies respectively correspond to the frequencies to which the relays associated with such track circuit are respectively tuned.

Other objects and features of my invention will be hereinafter more fully described and claimed.

In order that my invention may be more clearly understood, attent on is directedto the drawing accompanying and forming a part of this specification and in which the single figure is a diagrammatic view of an automatic railway block signaling system in accordance with my invention.

The drawing shows a portion of an automatic railway block signaling system and sufficient of the circuit connections thereof to illustrate my invention. In the drawing, reference characters A, B and C represent three blocks or track sections of the system, and S, S and S the signalsrespectively associated with and disposed at the entrance of said blocks or track sections for governing the same. In thi system traflic is supposed to proceed from right to left in the direction of the arrow, and the signals S, S and S are three-position signals which are normally held in clear position and which are respectively shown in caution, danger and clear positions. Each of the signals S, S and S etc., under the action of gravity, tends to assume danger position but is adapted to moved to and held in either clear or caution position by means of suitable motors, not shown. The motors for moving each of the signals to caution and clear positions are respectively included in caution motor-control and clear motor-control circuits, and in the drawing reference characters 1, 2 and 1, 2 respectively represent conductors of the caution motor-control circuits for signals S and S, and reference characters 3, 4i and 3', 4 conductors of the clear motor-control circuits for signals S and S. Relays R, R R and R are employed for respectively controlling the caution motor-control circuit of signal S, the clear motorcontrol circuit of signal S, the caution motor-control circuit of signal S and the clear motor-control circuit of signal S. The coils of the relays R and R are preferably connected in parallel across the rails of the block or track section A at the entrance end thereof, and the coils of the relays R and R are likewise preferably connected in parallel across the rails of the block or track section B at the entrance thereof. Current variations or fluctuations are adapted to be produced in the track circuits, preferably by means including sources of direct current, such as primary or storage batteries. As shown, this means consists of two alternating current generators G and G connected in parallel across the rails of the block A at the exit end thereof, two alternating generators G and G connected in parallel across the rails of the block B at the exit end thereof and primary or storage batteries for supplying direct current to the fields of the generators. Reference characters F, F F and F respectively represent the fields of generators G, G, G and G the fields F and F being connected to a suitable source of direct current supply such as the primary or storage battery M, through a switch 0 which is mechanically controlled in a conventional manner by the signal S, and the fields F and F being likewise connected to a source of direct current supply such as the primary or storage battery M, through a switch C, mechanically controlled by the signal S The frequencies of the alternating currents produced by generators G, G, G and G are all different and preferably different from the frequencies of the usual commercial altcrnatingcurrents; for example, they may be respectively 75 cycles, 250 cycles, 150 cycles and 300 cycles. The frequencies of the current produced by the generators for supplying current to the track circuit preceding the track section A may be and preferably are respectively the same as those of the currents produced by the generators G and G and the frequencies of the currents produced by the generators for the track section C may be and preferably are respectively the same as those of, the currents produced by the generators G and Gr, and so on. The relays R, R, R and R are frequency relays and are respectively suitably tuned as by means of adjustable condensers D, D, D and D to the frequencies.

of the alternating currents produced by the generators Gr, G G and G so that when either generator for a given track circuit is supplying alternating current to such cir- 'cuit only that relay in the circuit which is tuned to the frequency of such. current will be energized.

In the specific form of my invention shown, the arrangement is'such that when the signal for any given track section or block moves to danger position, it moves the switch controlling the field circuits of the generators for the track circuit of the preceding section or block to a position closing the field circuit of that generator for supplying to such track circuit alternating current of a frequency to which the relay in said track circuit controlling the caution motor-control circuit is tuned, thereby, suming such preceding track section or block to be unoccupied, effecting movement of the preceding signal to caution position; and when the signal for said given section or block moves from danger to either of its other positions, that is, caution or clear, it moves said switch to a position closing the field circuit of that generator for supplying to the track circuit of the preceding section or block, alternating current of a frequency to which the relay in said track circuit. for controlling the clear motor-control circuit is tuned, thereby, assuming such preceding section or block to be unoccupied, effecting movement of the preceding signal to clear position. It will thus be seen that when none of the track circuits are-short-circuited, all' the signals will be at clear. If,however, a train is present in any section or block, or the rails of such section or block are otherwise shortcircuited, the signal for-the immediate section will be set at danger, and the signal for the preceding section at caution.

Referring to the drawing, the operation of my improved system is as follows: A train T moving in the direction of the arrow and entering the section or block B, shortcircuits the relayR- with respect to generator G the field "circuit of which is now closed, whereupon the armature of this relay drops to a position opening the clear motor-control circuit 3, 4. for the signal S governing section or block B. The signal S will then move by gravity to danger position as shown, and in so moving it moves switch arm 5. of the switch C out of engagement with contact arm 13 thus opening the field circuit of generator G, and into engagement with the contact arm 6, thereby effecting the closing of the circuit of field F of generator G over the following path: from battery M through conductor 7, conductor 8, field F, conductor 9 to, the contact arm 6, then through the movable switch arm 5 and conductor 10 back to the battery. The circuit of the field F being broken, the track circuit of the section or block A will no longer be supplied with alternating current by the generator G and the relay R will accordingly be de-energized and its armature will drop to a position opening the clear motor-control circuit 3, 4. The generator G, however, will now supply alternating current to the track circuit of section A and relay B, being tuned to the frequency of this current, will be energized and move its armature to a position closing the caution motor-control circuit 1, 2, thereby effecting movement of signal S to caution position as shown. The signal-S for the block or section C now stands at clear, as shown, holding the switch arm 5 of switch C in engagement with the contact arm 13 and out of engagement with the contact arm 6- The circuit of the field F of the generator G is therefore open, and the circuit of field F for the generator G is closed over the following path: from battery M through conductor 7, conductor 11, field F- and conductor 12 to the contact arm 13, and then through the movable switch arm 5 and conductor 10 back to the battery. The train T now moving from the section or block B into the section C, short-circuits the relay (not shown) controlling the clear motor-control circuit for signal S as described above in connection with signal S,

and the signal S thereupon moves to danger position. In moving to danger position signal S moves switch arm 5' of switch C- out of engagement with contact arm 13, thereby opening the circuit of field F of the generator G and into engagement with the contact arm 6, thereby closingthe field circuit of generator G over thefollowingpathz from battery M, through conductor 7, conductor 8, field F and conductor 9 to the contact arm 6, then through switch arm 5 and conductor 10 back to the battery. The generator G will then supply alternating current of a givenfrequency to the track circuit of the section or block B,

and relay B being tuned to this frequency,

will be energized and move its armature to a position closing the caution motor-control circuit 1, 2, thereby effecting movement of signal S to caution position. Signal 8 in moving to caution position, moves switch arm 50f switch C out of engagement with contact arm 6, thereby opening the field circuit of generator G, and into engagement with contact arm13, thereby closing the field circuit of generator G over. the following path: from battery M through conductor 7, conductor 11, field F and conductor 12 to the contact arm 13, and then through switch arm 5 and conductor 10 back to the battery. The generator G will then supply alternating current of a given frequency to the track circuit ofthe section or block A, and relay B being tuned to this frequency, will be energized and move its armature to a posinumerous changes. and modifications without departure from the spirit of the invention and the scope of the appended claims.

For example, my invention contemplates the association with the sources of direct current, of means other than the alternating current generators shown for producing current variations or alternating currents in the track circuits.

Having now described my invention,what I claim as new and desire to protect by Letters Patent, is as follows:

1. In an automatic railway block signaling system, a series of signal-control circuits for the block signals, a series of track circuits, means for producing in each track circuit current variations of a given frequency but different from the frequency of the current variations produced in any adjacent track circuit, and devices for controlling the signal-control circuits respectively associated with said track circuits and respectively tuned to the frequency of the current variations in such track circuits, substantially as described. 7 p

2. In an automatic railway block signaling system, a series of signal-control circuits for the block signals, a, series of relay circuits respectively including relays for respectively controlling the signal-control circuits, and means for producing in each relay circuit current variations of a given frequency but different from the frequency of the current variations produced in the relay circuit for any adjacent block, the relay in. each circuit being tuned to the frequency of the current variations in such circuit, substantially as described.

3. In an automatic railway block signal ing system, a series of signal-control circuits for the block signals, a series of track circuits, means for producing in each track circuit alternating current of a given frequency but different from the frequency of the alternating current produced in any adj acent track circuit, and devices for controlling the signal-control circuits respectively associated with said track circuits and respectively tuned to the frequencies of the alternating currents in suchtrack circuits, substantially as described.

4:. In an automatic railway block signaling system, a. series of signal-control circuits for the block signals, a series of relay circuits respectively including relays for respectively controlling the signal-control circuits, and means for producing in each relay circuit alternating current of a given frequency but different from the frequency of the alternating current produced in the relay circuits for any adjacent block, the relay in each circuit being tuned to the frequency of the alternating current in such circuit, substantially as described.

5. In an automatic railway block signaling system, a plurality of tracksections or blocks, a signal for each block, a plurality of signal-control circuits for each signal, a plurality of relay circuits for each block respectively including relays for respectively controlling the signal-control circuits for such block, each of said relay circuits also including the rails of the correspondingtrack section or block, and means for producing in each of said relay circuits current variations of a given frequency but different from the frequency of the current variations produced in the other relay circuitfor the same block and also different from the frequency of the current variations in any of the relay circuits for any adjacent track section or block, the relay in each relay circuit being tuned to the frequency of the current variations produced in such circuit, substantially as described.

6. In an automatic railway block signaling system, a plurality of track sections or blocks, a signal for each block, a plurality of signal-control circuits for each signal, a plurality of relay circuits for each blockrespectively including relays for respectively controlling the signal-control circuits for such block, each of said relay circuits also including the rails of the corresponding track section or; block, means for producing in each of said relay circuits current variations of a given frequency but different from the frequency of the current variations produced in the other relay circuit for the same block and also different from the frequency of the current variations in any of the relay circuits for any adjacent track section or block, the relay in each relay circuit being tuned to the frequency of the current variations produced in such circuit, and

means controlled-by each signal for controlling the means for producing current varia tions in the relay circuits for an adjacent block, substantially as described.

7. In an automatic railway block signaling system, a series of relay circuits for the respective track sections or blocks and respectively including the rails of the respective track sections or blocks, and means for producing in each of said relay circuits current variations of a given frequency but different from the frequency of the current variations produced in the relay circuit for any adjacent block, each of said circuits including a relay tuned to the frequency of the current variations produced therein,substantially as described.

S. In a railway block signaling system, a series of signal circuits, a series of track circuits, means including a direct-current circuit associated with each track circuit for producing therein current variations of a given frequency but different from the current variations produced in any adjacent track circuit, and devices for controlling the signal circuits respectively associated with said track circuits and respectively tuned to the current variations in such track circuits, substantially as described.

9. In a railway block signaling system, a series of signal circuits, a series of track circuits, means including a direct-current circuit associated with each track circuit for producing therein alternating current of a given frequency but different from the frequency of the alternating current produced in any adjacent track circuit, and relays for controlling the signal circuits respectively associated with said track circuits and re spectively tuned to the frequencies of the alternating currents in the track circuits, substantially as described.

10. In an automatic railway block signaling system, a series of signals, a series of track circuits, means for producing in each track circuit current variations of a given frequency but different from the frequency of the alternating current produced in any adjacent track circuit, and means for controlling said signals including devices respectively associated with said track circuits and respectively tuned to the lfrequency of the current variations-in such track circuits, substantially as described.

ll. In an automatic railway block signal- 7 ing system, a series of signals, a series of track circuits, means for producing in each track circuit alternating current of a given frequency but different from the frequency of the alternating current produced in any adjacent track circuit, and signal controlling means including devices respectively associated with said track circuits and respectively tuned to the frequencies of the alternating currents in such track circuits, substantially as described.

12. In an automatic railway block signaling system, a plurality of track sections or blocks, signaling means for each block, a plurality of relay circuits for each block respectively including relays for controlling the signaling means for such block, each o f said relay circuits also including the rails of the corresponding track section or block, and means for producing in each of said relay circuits, current variations of a given frequency but different from the frequency of the current variations produced in the to the frequency of the current variations produced in such circuit, substantially as described.

13. In an automatic railway block signaling system, a plurality of track sections or blocks, signaling means including a signal for each block, a plurality of relay circuits for each block respectively including relays for controlling the signaling means for such block, each of said relay circuits also including the rails of the corresponding track section or block, means for producing in each of said relay circuits, current variations of a given frequency but difierent from the frequency of the current variations produced in the other relay circuit for the same block and also different from the frequency. of the current variations in any of the relay circuits for any adjacent track section or block, the relay in each relay circuit being tuned to the frequency olf the current varia tions produced in such circuit, and means controlled by each signal for producing cur rent variations in the relay circuits for an adjacent block, substantially as described.

This specification signed this 17th day of June, 1920.

ISAAC P. RODMAN.

Certificate of Correction.

It is hereby certified that in Letters Patent No; 1,405,005, granted January '31, 1922, upon the application of Isaac P. Rodman, of West Orange, New Jersey, for an improvement in Signaling Systems, errors appear in the printed specification requiring correction as follows: Page 2, line 24, after the Word to, first occurrence, insert the Word be; page 5, line 3, claim 10, strike out the Words alternating current and insert the words current variations; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 21st day of March, A. D., 1922.

[SEAL] I p WM. A. KINNAN,

' Acting Commissioner of Patents. 

